synchronized (
                    systemProperties) { // avoid concurrentmodification if someone else sets/removes an unrelated system
                // property
                this.systemProperties.putAll(systemProperties);
            }
        } else {
            this.systemProperties = null;
        }

        return this;
    }

    @Override
    public Properties getUserProperties() {

        validateFields(body.doc, this::throwValidationErrorApi);
        body.crudMode = CrudMode.CREATE;
        final Map<String, Object> doc = getDoc(body).map(entity -> {
            try {
                entity.putAll(fessConfig.convertToStorableDoc(body.doc));

                final String newId = ComponentUtil.getCrawlingInfoHelper().generateId(entity);
                entity.put(fessConfig.getIndexFieldId(), newId);

                [(jsonChange.toApiChange()): jsonChange.acceptation]
            }
            acceptedApiChanges.acceptedChanges.putAll(acceptedChanges)
        }
        return acceptedApiChanges
    }

    Map<String, String> toAcceptedChangesMap() {
        acceptedChanges.collectEntries { change ->

  }

  public final void testPutAll() {
    for (Table<Character, Integer, String> testInstance : getTestInstances()) {
      assertThrows(
          UnsupportedOperationException.class,
          () -> testInstance.putAll(ImmutableTable.of('a', 1, "blah")));
    }
  }

  public final void testRemove() {
    for (Table<Character, Integer, String> testInstance : getTestInstances()) {

        Properties merged = new Properties();
        if (sourceDominant) {
            merged.putAll(target.getProperties());
            merged.putAll(source.getProperties());
        } else {
            merged.putAll(source.getProperties());
            merged.putAll(target.getProperties());
        }
        target.setProperties(merged);
        target.setLocation(
                "properties",

                    ImmutableSetMultimap<String, Integer> badEntries =
                        ImmutableSetMultimap.of("foo", 314, "one", 159, "two", 265, "bar", 358);
                    multimap.putAll(badEntries);
                    return Multimaps.filterEntries(
                        multimap, not(Predicates.in(badEntries.entries())));
                  }
                })

        // ----------------------------------------------------------------------

        EnvironmentUtils.addEnvVars(systemProperties);
        SystemProperties.addSystemProperties(systemProperties);
        systemProperties.putAll(context.systemPropertiesOverrides);

        // ----------------------------------------------------------------------
        // Properties containing info about the currently running version of Maven

        fields.put(key, value);
    }

    @Override
    public Map<String, Object> toSource() {
        final Map<String, Object> sourceMap = super.toSource();
        if (fields != null) {
            sourceMap.putAll(fields);
        }
        return sourceMap;
    }

    @Override
    protected void addFieldToSource(final Map<String, Object> sourceMap, final String field, final Object value) {

        return systemProperties;
    }

    public MavenExecutionRequest getRequest() {
        return request;
    }

    public void setUserProperties(Properties properties) {
        this.userProperties.putAll(properties);
    }

    public Path getRootDirectory() {
        return rootDirectory;
    }

    public Path getTopDirectory() {
        return topDirectory;
    }

        transformValues(ImmutableMap.of("a", 1), Functions.toStringFunction());
    assertThrows(UnsupportedOperationException.class, () -> map.put("b", "2"));

    assertThrows(UnsupportedOperationException.class, () -> map.putAll(ImmutableMap.of("b", "2")));

    assertThrows(
        UnsupportedOperationException.class,
        () -> map.entrySet().iterator().next().setValue("one"));
  }

  public void testTransformRemoveEntry() {